1. Field of the Invention
The present invention relates to a polymer actuator and a method for manufacturing the same.
2. Description of the Related Art
Conductive polymers or conductive polymer materials, such as polymer gels containing conductive materials, are known to produce electrochemical expansion and contraction action. Utilizing the phenomenon, an attempt of putting a flexible actuator (polymer actuator) into practical use has been progressed. The application of such a polymer actuator not only to small-sized substances, such as artificial muscles, robot arms, artificial arms, and micromachines but also to large-sized substances has drawn attention.
Japanese Patent Laid-Open No. 2004-350495 discloses, as a curve driver for medical use or industrial use, a polymer actuator having a conductive layer covering the outer circumferential surface of a resin tube, four conductive polymer layers covering the outer circumferential surface of the conductive layer, and an electrolyte layer covering each conductive polymer layer. However, Japanese Patent Laid-Open No. 2004-350495 does not disclose a specific connection measure for securely connecting each conductive polymer layer with an external power supply.
In order to address the problem, Japanese Patent Laid-Open No. 2009-28143 discloses a structure for increasing the contact between a lead wire and the conductive polymer layers by the elastic pressing force of a coil, which is provided on the periphery of an actuator. According to the structure of Japanese Patent Laid-Open No. 2009-28143, the secure contact between an actuator electrode and the lead wire is expected but, in order to achieve the secure contact, the structure requires two or more members, such as a coil, an insulating film for preventing the coil from being energized, and an end member for facing the pressing force from the coil. In addition, the structure has a problem in that the ends of expanding and contracting conductive polymer layers are directly pressed and thus a load is applied to the pressed portions during deformation of the conductive polymer layers, resulting in the fact that the actuator easily deteriorates.